Various organizations such as governments, companies, and colleges use a relatively large scale storage system to manage data since a large amount and variety of data are handled. This storage system is configured by arranging a multiplicity of storage devices (e.g., hard disk drive (hereinafter, “HDD”)) into an array and provides a storage area based on RAID (Redundant Array of Independent (or Inexpensive) Disks), for example. At least one logical volume (hereinafter, “volume”) is formed on a physical storage area provided by a storage device group and this volume is provided to a host computer (hereinafter, “host”). The host transmits predetermined commands to the storage system to write/read data to/from the volume.
The above volume is a unit of the logical storage area provided by the storage device group, and a logical unit (LU) recognized as a unit logical storage area by the host is generated by setting a logical storage area created by one or a plurality of volumes such that the area becomes identifiable from the host.
Improvement in performance has been required for storage systems. PTL 1 discloses a technology related to higher performance of a storage system. Specifically, PTL 1 discloses a technology of preliminarily determining microprocessor packages (hereinafter, “MPPK”) responsible for respective volumes in a control unit executing data processes (such as writing and reading of data) in the volumes to store control information necessary for the processes in local memories within the MPPK. PTL 1 also discloses a technology of changing MPPK responsible for a process of a certain volume to another MPPK.